textproduct: Quad Cities

KEY MESSAGES

- Patchy frost is possible tonight along the Highway 20 corridor but confidence is low in this occurring due to winds and clouds. - Patchy/areas of frost possible Wednesday night along and north of Hwy 30.

- Below normal temperatures Wednesday and Thursday. A brief weekend warm-up will be followed by temperatures near normal next week.

- Isolated diurnal showers possible Friday, with a more substantial system Saturday night and Sunday bringing higher (40-50%) chances for precipitation.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 244 PM CDT Tue May 5 2026

Early afternoon water vapor imagery shows the CWA in a semi-zonal flow aloft with a weak shortwave over northeast KS. This wave is providing the lift for the scattered showers across central MO. Closer to home, dry northerly flow and deep mixing up to 850mb per our 18z sounding has kept dewpoints in the upper 20s/low 30s today. This has also kept any wetting rain further to our south and I have updated the forecast to remove mention of any precipitation for the rest of the day. A few sprinkles may still occur in west central IL, but no appreciable rain is expected.

Tonight...surface high to build into the upper Great Plains, with slightly colder and drier northerly low level flow advecting into the CWA. RAP 500-300mb RH profiles suggest high clouds to remain over much of the CWA and with north winds over 5kts, so I am not anticipating a complete drop in temps overnight that would necessitate a frost/freeze headline. That said, some river valleys and low lying drainage areas could still see some patchy frost develop. Overnight lows to drop into the middle 30s to lower 40s.

Wednesday...a rather chilly early May day is on tap, with continued CAA and a mix of sun/clouds keeping temperatures in the 40s/50s or closer to early April standards. A cold pocket aloft, steep low level lapse rates, and forecast soundings suggest we could see some diurnal Cu and maybe even a few showers develop in the afternoon. However, I have left out of the forecast for now given the dry sub- cloud layer/inverted-V soundings. Deep mixing may also bring some gusty winds over 20kts as well and will pass on to the overnight shift. In addition, all models show clouds clearing after sunset as a surface ridge slides east across IA and winds diminish. This will allow temps to drop back into the 30s, resulting in patchy/areas of frost primarily along and north of Hwy 30 and river valleys. NBM probabilities of temps<32 degrees is now 50-70% along and north of Hwy 30. While this is not record low territory yet (upper 20s/30s), a frost/freeze headline may be needed. Below normal temps look to persist into next week, as CPC 6-10 Day temperature outlook has 70% combined probs of near/below normal temperatures.

LONG TERM /THURSDAY THROUGH TUESDAY/

Issued at 244 PM CDT Tue May 5 2026

Northwesterly flow induced by a cutoff upper level low over Hudson Bay will continue to bring below-normal temperatures and mild weather to the area.

Embedded disturbances will move through the northwesterly flow Thursday and Friday, bringing a chance for precipitation Friday. The limiting factor for this will be how much moisture is available, as the continued northwesterly flow has established a very dry airmass over the region. This limited moisture keeps pops at 10% or below mention on Thursday. Greater confidence lies in Friday's precipitation chances (30-40%) as a plume of moisture moves into the Upper Midwest with an amplified wave. Total precipitation will likely be light, as NBM projections show a <20% chance of exceeding 0.25 inches of rain in 24 hours.

Saturday, high pressure to the southeast will allow for southerly low-level flow, bringing warm and moist air into the region. As a result, near-normal temperatures are expected Saturday. Following a pleasant Saturday, another disturbance will move through the area Sunday. Precipitation is likely (pops 50-70%) with this system, given the greater moisture, but uncertainty lies in the system's track. Recent trends show a southward shift, which decreases the amount of overall amount of precipitation across the area.

Northwest flow will return on Monday, bringing additional dry air in behind the departing system. Ensembles suggest that a disturbance will move through, though this system is not well defined at this time.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 630 PM CDT Tue May 5 2026

VFR TAFs are forecast through the period. A boundary is slowly shifting southward this evening that will turn the winds from northwest to north tonight with speeds around 5 to 10 knots. Skies will slowly clear this evening behind the boundary before more clouds overspread the area from west to east after 06 UTC. Gusty northwest winds are forecast to redevelop after 15 UTC on Wednesday with speeds of 10 to 15 knots and gusts of 20 to 25 knots. Ceilings are expected to remain above 8 kft through the period.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.